1. Field of the Invention
Embodiments of the invention relate to a stereoscopic image display and a driving method thereof.
2. Description of the Related Art
Stereoscopic image displays are categorized into a glasses type that requires the use of special glasses and a non-glasses type that does not require use of the special glasses. In the glasses type, a binocular parallax image is displayed on a direct view-based display device or a projector by changing a polarization direction or in a time division manner, and polarization glasses or liquid crystal shutter glasses are used to implement stereoscopic images. In the non-glasses type, generally, an optical plate such as a parallax barrier or the like for separating an optical axis of the binocular parallax image is provided in front of a display screen so that left-eye image light and right-eye image light are separated to implement stereoscopic images.
Glasses-type stereoscopic image displays are categorized into a polarization glasses type and a shutter glasses type. The polarization glasses type requires a polarization separation device, such as a patterned retarder, to be bonded to a display panel. The patterned retarder separates the polarizations of a left-eye image and a right-eye image displayed on the display panel, thereby creating a binocular parallax. As the polarizations of the left-eye image and the right-eye image are separated by the patterned retarder, a viewer wearing polarization glasses can see the left-eye image with the left eye and the right-eye image with the right eye and therefore can perceive a stereoscopic effect due to the binocular parallax. The patterned retarder may be implemented as a glass patterned retarder GPR based on a glass substrate or a film patterned retarder FPR based on a film substrate. In recent years, the film patterned retarder FPR, which can reduce the thickness, weight, price, etc., of the display panel compared to the glass patterned retarder GPR, has come to be more preferred.
If a stereoscopic image display that displays a stereoscopic image by the binocular parallax is unable to completely separate the left-eye image and the right-eye image, the viewer may feel or perceive a crosstalk where the left-eye image and the right-eye image overlap each other when viewing them with a single eye (left eye or right eye). A gray-to-gray (GTG) crosstalk is defined as a mean crosstalk for the gray levels.
On the screen (or pixel array) of the polarization glasses type stereoscopic image display, odd-numbered pixel lines (hereinafter, abbreviated as “odd lines” can display a left-eye image and even-numbered pixel lines (hereinafter, abbreviated as “even lines”) can display a right-eye image. In this polarization glasses type stereoscopic image display, gray-to-gray (GTG) crosstalk may be represented as a mean value of a perceived crosstalk for the gray levels of odd and even lines on the screen. In the polarization glasses type stereoscopic image display, there is as big a difference in gray level between data written to the pixels of odd lines and data written to the pixels of even lines, both of which are connected to the same data line, as the binocular disparity between the left-eye image and the right-eye image. Thus, the polarization glasses type stereoscopic image display is more susceptible to gray-to-gray crosstalk. In other words, the polarization glasses type stereoscopic image display shows a large difference in gray level between data voltages continuously supplied to the pixels of odd lines and the pixels of even lines, respectively, through the same data line.